Polls vary widely, and some still show Clinton with a more substantial lead over Trump. A Saturday IBD/TIPP Tracking poll reported that 45% of likely voters are backing Clinton and 41% plan to vote for Trump.

Yet others — such as the Friday Rasmussen Reports — showed the candidates in a tie. Saturday's LA Times/USC tracking poll had Trump with a two-point lead over Clinton.

The week of up-and-down polling comes as Trump continues to insist that the surveys are "rigged" against him.

Donald Trump and Hillary Clinton face off during US presidential debates

"I have no doubt about it," he told Fox News' Bill O'Reilly Thursday when asked about the possibility of "rigged" polls.

"I'm winning in certain polls and then in other polls, the dirty polls we call them, I was losing by numbers that were ridiculous," he said. "I think we're winning, but Bill, you look at some of these polls it's absolutely ridiculous."

Trump has repeatedly claimed the yet-to-be-held election is "rigged" against him, too. He has refused to say if he'll accept the results.